# Bound states in the continuum through environmental design

## TL;DR

This paper introduces a novel environmental engineering approach to realize bound states in the continuum (BICs) in photonic systems, enabling control over radiation channels and the creation of complex BIC configurations.

## Contribution

The study presents a new paradigm for BIC realization by environmental design, demonstrating BICs in photonic crystal slabs within engineered environments, including lines, points, and their intersections.

## Key findings

- BICs can be engineered through environmental control of radiation channels.
- Photonic crystal slabs exhibit both isolated and line BICs in different Brillouin zone regions.
- Line intersections of BICs and leaky resonances can produce exceptional points and bulk Fermi arcs.

## Abstract

We propose a new paradigm for realizing bound states in the continuum (BICs) by engineering the environment of a system to control the number of available radiation channels. Using this method, we demonstrate that a photonic crystal slab embedded in a photonic crystal environment can exhibit both isolated points and lines of BICs in different regions of its Brillouin zone. Finally, we demonstrate that the intersection between a line of BICs and line of leaky resonance can yield exceptional points connected by a bulk Fermi arc. The ability to design the environment of a system opens up a broad range of experimental possibilities for realizing BICs in three-dimensional geometries, such as in 3D-printed structures and the planar grain boundaries of self-assembled systems.